If, in theory, dismantling settlemets would bring about peace and a cessation of teror and hostility, most would agree that it is justified. After all, Judaism allows all Torah commandments save idolatry, adultery and murder, to be violated if it is necessary to save a life. One can certainly argue that achieveing peace is a life-saving accomplishment.
On the other hand, the Jewish People are commanded to dwell in their land. That is even obligatory if it means fighting. Otherwise, what is the difference between the West Bank and Tel Aviv? If Israel voluntarily dismantles itself and all the Jews move to the US, that may be said to bring about peace and save lives. Yet no one in their right mind would suggest such a thing.
So is one part of the Land of Israel different than the whole of the Land? I think yes, and historically we find that King Solomon gave cities in the North to the King of Tyre. So perhaps a small territorial gift that enables the rest to live in peace is justified.
The problem with all this talk is that it is based on a theoretical that is non-existent. There is no guarantee that ceding territory and dismantling settlements will bring peace. There is a guarantee that it would weaken Israel strategically. It seems to me that the "life-saving" argument actually goes the other way and forbids giving away territory.
But it's not just theory, there is precedent. Israel unilaterally withdrew from the Gaza strip. Thousands of families in dozens of settlements were uprooted. The end result? Missile fire and terrorism. No peace.
There is no reason to think that further uprootings would have any different result.
Also, the western world does not know how small Israel is. To leave the post '67 areas would again leave Israel with a narrow belly of only 11 miles! Imagine putting enemy guns across the Hudson and trying to keep New York safe. Same deal. The heavily populated central Israel area would be only 11 miles from Arabs. If they follow Gaza precedent, all of Tel Aviv will be in and out of bomb shelters.
Nope, saving lives implies keeping the settlements and the territories. Only if there is a clear destination of peace could we even think of compromise. There is no such destination, and there is no partner ready for it. If they wanted peace, they'd have had it long ago. They want Israel to be theirs to transform into Palestine, and eliminate the Jewish State.
Read the news, the leaders can't bring themselves to recognize that Israel is a Jewish State.
Sorry to disappoint, but reality must be faced.